Secondary battery

ABSTRACT

A secondary battery for an electronic appliance, including a battery cell. The battery cell has a positive electrode, a negative electrode, and an electrolyte in a pack. A positive electrode terminal and a negative electrode terminal are led out from the same side face of the pack. A metallic battery can accommodates the battery cell therein such that the side face from which the positive electrode terminal and the negative electrode terminal are lead out is faced towards the opening side. A lid, made of a synthetic resin, in which terminal parts to be connected to the electrodes of the electronic appliance upon being connected to the positive electrode terminal and the negative electrode terminal are faced outwardly, plugs the opening of the battery can, the battery cell being accommodated in the battery can upon being adhered onto an inner face thereof.

CROSS REFERENCES TO RELATED APPLICATIONS

The application is a continuation of U.S. application Ser. No.11/495,658, filed Jul. 31, 2006, and is based upon and claims thebenefit of priority from prior Japanese Patent Application JP2005-234937, filed Aug. 12, 2005, the entire contents of both of whichare incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a secondary battery having an electrode body asa generating element which is accommodated in a pack, from whichelectric power as generated by the electrode body is taken out through apair of positive and negative electrode terminals, such as lithium ionsecondary batteries and lithium polymer secondary batteries.

2. Description of the Related Art

In recent years, the demand for portable electronic appliances includinginformation appliances such as notebook personal computers, mobilecommunication instruments such as mobile telephones, and video camerasis increasing rapidly. Sealed small-sized secondary batteries such asnickel-cadmium batteries, nickel hydrogen batteries, and lithium ionbatteries are frequently used as a power source of such an electronicappliance. Above all, lithium ion secondary batteries are employed invarious fields while making the most of characteristics such as highvoltage, high energy density and lightweight.

In particular, as a countermeasure to the liquid leakage which isproblematic in the case of using a liquid based electrolytic solution,for example, there is proposed a so-called polymer lithium ion secondarybattery using, as an electrolyte, a gel-like polymer film having apolymer impregnated with a non-aqueous electrolytic solution or by usingan electrolyte in a fully solid state.

Such a polymer lithium ion secondary battery is being further developedfor the purpose of meeting the demands for respective electronicappliances in recent years, such as downsizing, lightweight andslimming, while making the most of a characteristic that a degree offreedom of the battery shape is high in addition to the characteristicsof a battery such as high energy density and lightweight.

Usually, in such a battery, for example, as illustrated in FIG. 37, asingle cell 301 made of a laminate of battery elements is accommodatedtogether with a connecting substrate 302 provided with a protectivecircuit and terminals in a pair of upper and lower plastic cases 303,304, thereby forming a battery pack 300 (see, for example, PatentDocument 1). Joining of the plastic cases 303, 304 having the singlecell 301 accommodated therein is usually carried out by ultrasonicwelding.

Here, in order to ensure mechanical strengths against falling, vibrationor the like, the battery pack 300, an exterior of which is configured bythe plastic cases 303, 304, is required to be formed so as to have aconsiderable thickness, and therefore, it was difficult to devise toachieve downsizing or slimming of the battery pack 300 itself.

Patent Document 1: JP-A-2002-8606

SUMMARY OF THE INVENTION

According to an embodiment of the invention, there is provided asecondary battery which makes the most of advantages of a secondarybattery represented by polymer lithium ion secondary batteries and whichis able to appropriately meet the demands for electronic appliances inrecent years such as downsizing, lightweight and slimming.

In order to solve the foregoing problems, according to an embodiment ofthe invention, there is provided a secondary battery for electronicappliance to be installed in an electronic appliance, thereby feeding anelectric power to the electronic appliance, the secondary battery beingprovided with a battery cell in which a positive electrode, a negativeelectrode and an electrolyte are accommodated in a pack, and a positiveelectrode terminal and a negative electrode terminal from the positiveelectrode and the negative electrode, respectively are lead out from thesame side face of the pack; a metallic battery can in which one openingfrom which the battery cell is inserted is formed and which accommodatesthe battery cell therein such that the side face from which the positiveelectrode terminal and the negative electrode terminal are lead out isfaced towards the opening side; and a lid made of a synthetic resin inwhich terminal parts to be connected to the electrodes of the electronicappliance upon being connected to the positive electrode terminal andthe negative electrode terminal and being faced outwardly are providedand which plugs the opening of the battery can, the battery cell beingaccommodated in the battery can upon being adhered onto an inner facethereof.

In accordance with the secondary battery according to an embodiment ofthe invention, since the battery cell is adhered onto an inner face ofthe battery can, it is possible to prevent unsteadiness of the batterycell within the battery can and to absorb an impact as caused due tofalling or vibration of the battery can or the like, thereby preventinga phenomenon that the impact is applied to a joining part among thepositive electrode terminal and the negative electrode terminal and theterminal parts from occurring. By achieving adhesion via an elasticmember or folding an overlap width of the battery cell along a side facethereof and then inserting it into the battery can, the elastic memberor the folded overlap width can function as a buffer member between thebattery cell and the battery can.

In addition, in the secondary battery, when the battery cell is insertedinto the battery can upon sticking an insulating film to the elasticmember, the insulating film is arranged along the side face of thebattery cell to cover an aluminum layer of the pack which is exposed onthe cut face of the overlap width part, it is possible to devise toachieve insulation from an inner wall of the battery can. Accordingly,even in the case where the metallic battery can is charged, it ispossible to prevent electrolytic corrosion as caused by conductancebetween the battery can and the aluminum layer of the pack fromoccurring.

Furthermore, in the secondary battery, the battery can and the lid areeach formed in a substantially trapezoidal shape with respect to thecross section thereof such that an edge in each side of the short sidesis formed in a circular arc shape, and the battery installing part inthe side of the electronic appliance is also formed in the same shape.Thus, in the case where the insertion face is turned inside out, sincethe edge of the battery installing part and the edge of the secondarybatter interfere with each other, thereby inhibiting the insertion, itis possible to surely prevent erroneous insertion.

In addition, in the secondary battery, by forming each of the batterycan and the battery cell in a substantially trapezoidal shape withrespect to the cross section thereof such that an edge in each side ofthe short sides is formed in a circular arc shape, it is possible toprevent erroneous insertion of the battery cell into the battery can andto effectively utilize a space within the battery can. In this way, itis possible to provide a clearance which becomes a margin when thebattery cell is heat expanded between the battery cell and the innerperiphery of the battery can. Accordingly, even in the case where thebattery cell is heat expanded, distortion is not generated in thebattery can, or an excessive load is not applied to the joining partamong the positive electrode terminal and the negative electrodeterminal and the terminal parts.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

FIGS. 1A and 1B are oblique views to show an example of an electronicappliance using a secondary battery to which the invention is applied.

FIG. 2 is an oblique view to show a secondary battery to which theinvention is applied.

FIG. 3 is a detailed oblique view to show a secondary battery to whichthe invention is applied.

FIGS. 4A and 4B are oblique views to show a state that a secondarybattery to which the invention is applied is installed in a batteryaccommodating part of an electronic appliance.

FIGS. 5A and 5B are oblique views to show other example of a secondarybattery to which the invention is applied.

FIG. 6 is a side view to show a state that a secondary battery to whichthe invention is applied is installed in a battery installing part whichis provided outside an electronic appliance or the like.

FIG. 7 is an oblique view of a battery can into which a battery cell isinserted.

FIGS. 8A and 8B are side views to show a state that an electrode part isprovided in an engagement member of a battery installing part which isprovided outside an electronic instrument or the like.

FIGS. 9A to 9C are views to show a secondary battery to which anexternal label is stuck, in which FIG. 9A is a back view, FIG. 9B is aplan view, and FIG. 9C is a front view.

FIG. 10 is a cross-sectional view of a second battery to show a statethat a battery lid is assembled.

FIG. 11 is a detailed oblique view to show a battery cell.

FIG. 12 is a cross-sectional view to show the structure of a pack of abattery cell.

FIGS. 13A and 13B are side views to show joining between a positive ornegative electrode terminal of a battery cell and a positive or negativeelectrode tab.

FIG. 14 is a side view to show a joining part between a positive ornegative electrode terminal and a positive or negative tab.

FIGS. 15A and 15B are oblique views to show a secondary battery in whichthe arrangement of positive and negative electrode terminal parts ismade different depending upon the function.

FIGS. 16A and 16B are oblique views to show other secondary battery inwhich the arrangement of positive and negative electrode terminal partsis made different depending upon the function.

FIGS. 17A to 17C are oblique views to show other example of a secondarybattery to which the invention is applied.

FIGS. 18A to 18L are views to show a process chart of a manufacturingprocess of a secondary battery to which the invention is applied.

FIG. 19 is a side view to show a battery cell, a holder and a substrateas placed in a jig.

FIG. 20 is an oblique view to show a battery cell which is inserted intoa battery can.

FIGS. 21A to 21C are cross-sectional views to show a state of a batterycell within a battery can.

FIGS. 22A to 22C are cross-sectional views to show a state that abattery cell is adhered within a battery can using an adhesive.

FIG. 23 is a cross-sectional view to show a state of a battery cellwhich is adhered within a battery can as adhered by an adhesive.

FIG. 24 is an oblique view to show other example of a secondary batteryto which the invention is applied.

FIG. 25 is an oblique view to show a cell stack.

FIG. 26 is an oblique view to show a cell aggregate.

FIG. 27 is an oblique view to show a secondary battery to which theinvention is applied.

FIG. 28 is an oblique view to show a cell aggregate in which an overlapwidth is folded.

FIG. 29 is a front view to show a substrate in which positive andnegative electrode terminals as lead out from a cell stack are welded.

FIG. 30 is an oblique view to show a battery charger for a secondarybattery to which the invention is applied.

FIG. 31 is a front view to show a secondary battery which is installedin the foregoing battery charger.

FIG. 32 is an oblique view to show other example of a battery chargerfor a secondary battery to which the invention is applied.

FIGS. 33A and 33B are cross-sectional views to show the foregoingbattery charger in which a secondary battery is installed.

FIG. 34 is an oblique view to show the foregoing battery charger inwhich a holding arm is accommodated.

FIG. 35 is an oblique view to show other example of a battery chargerfor a secondary battery to which the invention is applied.

FIGS. 36A and 36B are oblique views to show the foregoing batterycharger in which a secondary battery is installed.

FIG. 37 is an oblique view to show a related-art polymer lithium ionsecondary battery.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The secondary battery to which the invention is applied will behereunder described in detail with reference to the accompanyingdrawings. A secondary battery 1 to which the invention is applied is,for example, a polymer lithium ion secondary battery and as illustratedin FIGS. 1A and 1B, is used for various electronic appliances, forexample, electronic appliances such as a digital still camera 10.Concretely, when accommodated in a battery accommodating part 12 asprovided inside a grip part 11 of a digital still camera 10 asillustrated in FIG. 1A, the secondary battery 1 supplies a drive powerto this digital still camera 10. The battery accommodating part 12 ismade of a substantially flat concave in response to the shape of thesecondary battery 1 and when a battery lid 14 as provided rotatably in abottom face part 13 of the digital still camera 10 is opened, is facedoutwardly. Furthermore, in the battery accommodating part 12,accommodating part electrodes which are brought into contact withelectrode terminal parts 37, 38 which are provided in the secondarybattery 1 as described later are formed in the bottom part. Further,when the secondary battery 1 is accommodated in the batteryaccommodating part 12 such that an end face on which the electrodeterminal parts 37, 38 are provided is an insertion end, the secondarybattery 1 is connected to the accommodating part electrodes, therebysupplying a power to the digital still camera 10. Incidentally, thebattery accommodating part 12 is provided with an energizing member (notillustrated) for discharging the secondary battery 1 from the batteryaccommodating part 12 and an engagement member 19 for engaging thesecondary battery 1 within the battery accommodating part 12 inopposition to the energizing member. This engagement member 19 will bedescribed later.

The secondary battery 1 will be hereunder described. As illustrated inFIG. 2 and FIG. 3, a battery cell 3 having electrode terminals packedtherein is inserted from an opening of a metallic battery can 2 which isformed in a substantially flat form, and the opening of the metallicbattery can 2 is plugged by a battery lid 4 provided with terminal partsto which a positive electrode terminal and a negative electrode terminalas lead out from the battery cell 3 are connected, thereby forming thissecondary battery 1.

The battery can 2 is made of a metallic casing in which one face of asubstantially flat cube is opened and is formed in a substantiallytrapezoidal shape with respect to the cross section thereof such that anedge in each side of the short sides is formed in a circular arc shapeas illustrated in FIG. 3. This battery can 2 is formed in asubstantially flat cube in which an opening 5 for inserting the batterycell 3 is formed only on one face by molding a metallic material such asiron by deep drawing. By regulating a wall thickness at approximately0.3 mm, this battery can 2 is formed in a slim shape such that when anaccommodating region of the battery cell 3 is eliminated, its ownthickness is controlled to the utmost; and at the same time, by usingthe metallic material, the battery can 2 can be provided with variousimpact resistances against falling, vibration, and so on, or withmechanical strengths against a sharp knife or the like, therebypreventing deformation, perforation or the like from occurring. Theopening 5 is an insertion end from which the battery cell 3 is insertedand after insertion of the battery cell 3, is plugged by the battery lid4. For that reason, plural engagement holes 6 with which engagementconvexes 47 as projected on the battery lid 4 are perforated in theperiphery of the opening 5. In the engagement holes 6, when the batterylid 4 is inserted into the opening 5, the engagement convexes 47 asprojected on the battery lid 4 invade into the opening 5 while beingwarped and are then engaged with the engagement holes 6. In this way,the battery lid 4 is assembled in the battery can 2.

When the shape of the battery accommodating part 12 into which thesecondary battery 1 is inserted together with the battery can 2 isformed in a substantially trapezoidal shape with respect to the crosssection thereof such that an edge in each side of the short sides isformed in a circular arc shape as illustrated in FIG. 4A, an insertionface of the secondary battery 1 into the battery accommodating part 12of the digital still camera 10 is defined so that erroneous insertioncan be prevented. That is, as illustrated in FIG. 4A, in the case wherethe insertion face of the secondary battery 1 is right, the sides of theshort sides of the battery accommodating part 12 are coincident with theshape of the principal face of the sides of the short sides of thesecondary battery 1 so that the secondary battery 1 can be smoothlyinserted. On the other hand, as illustrated in FIG. 4B, in the casewhere the insertion face of the secondary battery 1 is reversed,square-shaped edges in the side of the long sides of the secondarybattery 1 are interfered by the edges formed in a circular arc shape inthe sides of the short sides of the battery accommodating part 12 sothat the insertion of the secondary battery 1 can be inhibited. In thisway, in the case where the insertion face is reversed in the back andfront, not only the insertion of the secondary battery 1 into thebattery accommodating part 12 can be prevented, but also a user caneasily confirm correctness of the insertion face of the secondarybattery 1.

Incidentally, in the case where the secondary battery 1 is externallyattached in a battery installing part as formed in the casing of anelectronic appliance separately from the battery accommodating part 12in the bottom face part 7 opposing to the opening 5 or is installed in abattery installing part of a battery charger 80 as illustrated in FIGS.5A, 5B, and 30, an engagement hole 8 to be engaged with an engagementmember 9 as projected in the battery installing part of the electronicappliance or battery charger may be formed in the battery can 2 asillustrated in FIG. 6. As illustrated in FIG. 7, since a concave 29 isgenerated on an insertion end face 3 b of the battery cell 3 asdescribed later, when this engagement hole 8 is formed corresponding tothe concave 29, it is formed without interfering with a battery element20 which is configured to have a positive electrode, a negativeelectrode and an electrolyte as accommodated within the battery cell 3.

Incidentally, FIG. 5A is a view to show an example in which anengagement hole 8 is formed over the full length in a longitudinaldirection of the bottom face part 7; and in this case, in the batterycan 2, a first winding part 17 is not provided in an external label 15as described later, and the bottom face part 7 is exposed externallyover the full length. Furthermore, FIG. 5B is a view to show an examplein which one pair of engagement holes 8, 8 are formed in both end partsin a longitudinal direction of the bottom face part 7; and in this case,a first winding part 17 for sticking a region exclusive of the both endparts in which the engagement holes 8, 8 are formed is provided in theexternal label 15.

Further, as illustrated in FIG. 6, when the secondary battery 1 isengaged with the engagement member 9 which is rotatably energized in anengagement direction of the battery can 2, the secondary battery 1 canbe externally attached in the outside of a casing of an electronicappliance or the like. In this way, in addition to the secondary battery1 which is accommodated in the battery accommodating part, the separatesecondary battery 1 can be easily externally attached in the electronicappliance, whereby the use time of the electronic appliance can beextended.

The engagement hole 8 is not limited to the examples as illustrated inFIGS. 5A and 5B but can be properly formed in an arbitrary shape.Furthermore, an engagement concave may be provided in the batteryinstalling part, thereby forming an engagement convex provided with ashape corresponding to the engagement concave in the bottom face part 7of the battery can 2.

Incidentally, with respect to the secondary battery 1 to which theinvention is applied, in addition to an embodiment in which a positiveelectrode terminal part 37 and a negative electrode terminal part 38 areformed and faced outwardly from a terminal hole 48 as formed on a frontface 1 c as described later, there may be employed an embodiment inwhich not only a positive electrode terminal part 37 is formed in asubstrate 35, but also the engagement hole 8 as formed in the bottomface part of the metallic battery can 2 is used as a negative electrodeor an earth electrode. In this case, as illustrated in FIG. 8A, a canbottom electrode 57 which becomes a negative electrode or an earthelectrode is provided in a place for forming the engagement hole 8 inthe bottom face part 7 of the battery can 2 and faced outwardly via theengagement hole 8. In this can bottom electrode 57, a negative electrodeline or an earth line as connected to the substrate 35 is drawn aroundand connected. Furthermore, in the engagement member 9 which is engagedwith this engagement hole 8, an electrode part 9 a as connected to anelectrode or an earth part in the electronic appliance side is formedand connected to the can bottom electrode 57 at the time of engaging theengagement hole 8 of the secondary battery 1.

Furthermore, in the battery can 2, after the battery lid 4 is connected,the battery cell 3 is inserted, and the opening 5 is plugged by thebattery lid 4, the insulating external label 15 is stuck. The externallabel 15 becomes a decorative label of the secondary battery 1 and alsodevises to achieve insulation of the metallic battery can 2. Asillustrated in FIG. 3, the external label 15 is provided with aprincipal face part 16 for winding the outer periphery of the batterycan 2 over the opening 5 and the bottom face part 7, a first windingpart 17 for winding a region exclusive of the both end parts in alongitudinal direction of the bottom face part 7, and a second windingpart 18 for winding a region exclusive of a terminal hole 48 as formedin a top cover 36 of the battery lid 4.

In the external label 15, since the battery can 2 is formed in a flatshape, a sticking work is easy, and the external label 15 is hardlyseparated as compared with the case of sticking it directly on thesurface of the battery cell 3 as configured to pack the battery element20. The first winding part 17 which is wound in the bottom face part 7of the battery can 2 is formed in a length shorter than that of thebottom face part 7 and stuck to the bottom face part 7 so that both endparts 7 a, 7 b in a longitudinal direction of the bottom face part 7 areexposed outwardly. In the battery can 2, an end part of the bottom facepart 7 is formed as an engagement part which is engaged with theengagement member 19 as provided in the battery accommodating part 12 ofthe digital still camera 10. That is, as illustrated in FIGS. 9A and 9B,the secondary battery 1 is formed as an engagement region with which theengagement member 19 in a hook shape for holding the battery can 2 inthe battery accommodating part 12 of the digital still camera 10 isengaged. Accordingly, in installing the secondary battery 1, theengagement member 19 is engaged. In this way, the secondary battery 1which is always energized towards the outside of the batteryaccommodating part 12 by an energizing member is engaged with thebattery accommodating part 12 in opposition to the energizing force.Furthermore, when the engagement member 19 comes off from the bottomface part 7 of the engagement member 19, the secondary battery 1 isdischarged from the battery accommodating part 12.

Here, where the first winding part 17 of the external label 15 isentirely stuck on the bottom face part 7, the engagement member 19 rubsthe first winding part 17 every time when the secondary battery 1 isinserted into and detached from the battery accommodating part 12,whereby the external label 15 is gradually rubbed and separated. At thisissue, since the external label 15 is wound in a region exclusive of theengagement part, the secondary battery 1 is free from rubbing by theengagement member 19 even in the case where it is repeatedly insertedinto and detached from the battery accommodating part 12.

Furthermore, in the secondary battery 1, a region of the bottom facepart 7 where the first winding part 17 is stuck is corresponding to aregion for forming the electrode terminal parts 37, 38 of the batterylid 4. Accordingly, even in the case where the secondary battery 1 isinstalled in the battery accommodating part 12 or battery charger 80while reversing the insertion direction, the insulating external label15 as stuck to the bottom face part 7 of the battery can 2 comes intocontact with the electrode terminal of the accommodating part electrodeor the battery charger 80 as provided in the bottom face part of thebattery accommodating part 12 corresponding to the electrode terminalparts 37, 38, whereby a danger of short circuit as caused due to thedirect contact with the metallic battery can 2 can be prevented.

Furthermore, as illustrated in FIG. 9C, the second winding part 18 ofthe external label 15 is to enhance an assembling strength between thebattery lid 4 and the battery can 2 upon being wound in a regionexclusive of the terminal hole 48 as formed on the top cover 36 of thebattery lid 4. When the assembling strength between the battery lid 4and the battery can 2 is enhanced by the second winding part 18, asillustrated in FIG. 10, by making an engagement depth between theengagement convex 47 as provided on the top cover 36 of the battery lid4 and the engagement hole 6 which is engaged with the engagement convex47 as provided in the periphery of the opening 5 of the battery can 2 asdescribed later large and protecting the engagement convex 47 on theupper face of the battery can 2 from the engagement hole 6, it becomesun-necessary to enhance the assembling strength between the battery can2 and the battery lid 4. Accordingly, it is possible to obtain a desiredassembling strength without hindering the flatness or appearance of thesecondary battery 1.

Incidentally, an information label 49 on which a variety of informationof the secondary battery 1 is described is stuck in the principal facepart of the side of the long sides of the battery can 2.

Next, the battery cell 3 which is accommodated in the battery can 2 willbe described below. As illustrated in FIGS. 3 and 11, in the batterycell 3, a strip positive electrode and a strip negative electrode arestacked via a polymer electrolyte layer and/or a separator; the batteryelement 20 as wound in a longitudinal direction is packed in a pack 23;and a positive electrode terminal 21 and a negative electrode terminal22 are lead out outwardly from the positive electrode and the negativeelectrode, respectively.

In the positive electrode, a positive electrode active substance layeris formed on a strip positive electrode collector, and a polymerelectrolyte layer is further formed on the positive electrode activesubstance layer. Furthermore, in the negative electrode, a negativeelectrode active substance layer is formed on a strip negative electrodecollector, and a polymer electrolyte layer is further formed on thenegative electrode active substance layer. The positive electrodeterminal 21 and the negative electrode terminal 22 are welded to thepositive electrode collector and the negative electrode collector,respectively. Furthermore, the positive electrode terminal 21 is made ofaluminum (Al), and the negative electrode terminal 22 is formed by usingnickel (Ni). These positive electrode terminal 21 and negative electrodeterminal 22 are connected to a positive electrode tab 31 and a negativeelectrode tab 32 as held in the battery lid 4 as described later,respectively and coupled with a positive electrode terminal board 33 anda negative electrode terminal board 34 as similarly provided in thebattery lid 4 via these positive electrode tab 31 and negative electrodetab 32, respectively.

The positive electrode can be configured by using, as a positiveelectrode substance, a metal oxide, a metal sulfide or a specificpolymer depending upon the kind of the targeted battery. For example, inthe case of configuring a lithium ion battery, it is possible to use alithium composite oxide containing, as the major component, Li_(x)MO₂(wherein M represents one or more kinds of a transition metal; and xvaries depending upon the charge/discharge state of the battery and isusually from 0.05 to 1.10) as the positive electrode active substance.As the transition metal M which configures the lithium composite oxide,Co, Ni, Mn, and so on are preferable. Specific examples of such alithium composite oxide include LiCoO₂, LiNiO₂, LiNi_(y)Co_(1-y)O₂(wherein 0<y<1), and LiMn₂O₄. Such a lithium composite oxide is able togenerate a high voltage and become a positive electrode active substancewhich is excellent in energy density. Furthermore, lithium-free metalsulfides or oxides such as TiS₂, MoS₂, NbSe₂, and V₂O₅ can also be usedas the positive electrode active substance. A combination of pluralkinds of these positive electrode active substances may be used.Furthermore, in forming a positive electrode by using such a positiveelectrode substance, known conductive agents or binders or the like canbe added.

A material capable of doping or dedoping lithium can be used as thenegative electrode material. For example, sparingly graphitized carbonbased materials or carbon materials of a graphite based material can beused. More specifically, there can be used carbon materials such as heatdecomposable carbons, cokes (for example, pitch coke, needle coke, andpetroleum coke), graphites, vitreous carbons, organic polymer compoundcalcined bodies (materials resulting from carbonization by calcining aphenol resin, a furan resin, etc. at an appropriate temperature), carbonfibers, and active carbons. Besides, polymers such as polyacetylene andpolypyrrole and oxides such as SnO₂ can be used as the material capableof doping or dedoping lithium. In forming a negative electrode from sucha material, known binders or the like can be added.

The polymer electrolyte is one as prepared by mixing a polymer material,an electrolytic solution and an electrolyte salt and incorporating thegelled electrolyte into the polymer. The polymer material has propertiessuch that it is compatible with the electrolyte solution. Examplesthereof include silicon gels, acrylic gels, acrylonitrile gels,poly-phosphazene-modified polymers, polyethylene oxide, andpolypropylene oxide, and composite polymers, crosslinked polymers ormodified polymers thereof; and fluorine based polymers such aspoly(vinylidene fluoride), poly(vinylidenefluoride-co-tetrafluoropropylene), and poly(vinyldienefluoride-co-trifluoroethylene) and mixtures thereof.

The electrolytic solution component includes an aprotic solvent which isable to disperse the foregoing polymer material therein, for example,ethylene carbonate (EC), propylene carbonate (PC), and butylenecarbonate (BC). As the electrolyte salt, one which is compatible withthe solvent is used, and a combination of a cation and an anion is used.Examples of the cation which can be used include alkali metals andalkaline earth metals. Examples of the anion which can be used includeCl⁻, Br⁻, I⁻, SCN⁻, ClO₄ ⁻, BF₄ ⁻, PF₆ ⁻, and CF₃SO₃ ⁻. Concretely,lithium hexafluorophosphate or lithium tetra-fluorophosphate is used asthe electrolytic salt in a concentration such that it can be dissolvedin the electrolytic solution.

As illustrated in FIG. 11, the pack 23 which accommodates the batteryelement 20 therein is formed by cutting a cell aggregate 27 (see FIG.30) having a substantially rectangular accommodating sheet 24 in whichplural accommodating concaves 25 for accommodating the battery element20 therein are arranged in advance and a sealing sheet 26 as welded onthe accommodating sheet 24 in which the battery element 20 isaccommodated and capable of sealing each of the accommodating concaves25 for every battery element 20.

The accommodating sheet 24 is formed in a longitudinal shape such thatthe plural accommodating concaves 25 are arranged via an overlap width28 with a prescribed width. The accommodating concaves 25 are formed ina substantially rectangular shape depending upon the shape of thebattery element 20. Furthermore, the arrangement direction of theaccommodating concaves 25 is not limited to the direction of the shortside as illustrated in FIG. 11, but the accommodating concaves 25 may bearranged in a direction of the long side or may be arranged lengthwiseand crosswise. The overlap width 28 spacing the respective accommodatingconcaves 25 is a joining face of the sealing sheet 26 for sealing theaccommodating concaves 25. Further, when the battery element 20 isaccommodated in each of the accommodating concaves 25 as illustrated byan arrow A in FIG. 11, the sealing sheet 26 is heat welded on theoverlap width 28, thereby forming the cell aggregate 27 having thebattery elements 20 integrated therein.

Incidentally, at this time, the positive electrode terminal and thenegative electrode terminal as extended from the positive electrode andthe negative electrode are lead out in the same direction from thejoining part with sealing sheet 26. Furthermore, at this time,evacuation is carried out simultaneously with the welding by using avacuum pump (not illustrated). Due to this suction force, the batteryelement 20 is sealed in the accommodating concave 25 covered by theaccommodating sheet 24 and the sealing sheet 26. Moreover, by suckingthe inside of the accommodating concave 25, the pack 23 foraccommodating the battery element 20 therein is drawn and squeezed andis formed in a substantially trapezoidal shape with respect to the crosssection thereof such that an edge in each side of the short sides isformed in a circular arc shape, in which a second face side which is thebottom face side of the accommodating concave 25 is small, whereas afirst face side which is the opening side is large, depending upon theshape of the battery element 20.

Furthermore, in the battery cell 3, a clearance is provided between thebattery element 20 and the accommodating sheet 24 in such a manner thatthe battery element 20 is not pressed against the side face of theaccommodating concave 25. Further, when the accommodating sheet 24 andthe sealing sheet 26 are sealed while being drawn ad squeezed, theconcave 25 is formed on the face in the side opposite to the batterycell 3 from which the positive electrode terminal 21 and the negativeelectrode 22 are lead out (see FIG. 7). Moreover, after sealing theaccommodating sheet 24 and the sealing sheet 26, in each of the batterycells 3, the principal face in the side of the sealing sheet 26 isformed in a flat shape by pressing. Thereafter, the cell aggregate 27 iscut along the overlap width 28 and separated every pack 23 having thebattery element 20 sealed therein, thereby forming the battery cells 3.

Incidentally, in addition to the formation of the battery cell 3 byforming the cell aggregate 27 and cutting it along the overlap width 28,the battery cell 3 may be formed by accommodating the battery element 20in a previously cut accommodating sheet for every individual batterycell and joining with a sealing sheet which is similarly cut for everyindividual battery cell.

Each of the accommodating sheet 24 and the sealing sheet 26 whichconfigure the pack 23 has a stack structure in which a polypropylene(PP) layer 52, an aluminum (Al) layer 53, and a nylon layer 54 arestacked in this order from the inside as illustrated in FIG. 12. Here,the aluminum layer 53 is used for the purpose of preventing the invasionof moisture into the pack 23 and preventing the expansion of the batteryelement 20. Furthermore, the polypropylene layer 52 not only preventsthe denaturation of the polymer electrolyte but also becomes a joiningface between the accommodating sheet 24 and the sealing sheet 26. Thatis, joining of the accommodating sheet 24 and the sealing sheet 26 iscarried out by opposing the polypropylene layers 52 to each other andheat melting them at about 170° C.

Incidentally, the configuration of the pack 23 is not limited thereto,but laminate films having various materials and stack structures and thelike can be employed. Furthermore, the joining method is not limited tothe heat melting. Examples of the configuring material of the pack 23include aluminum, polyethylene terephthalate (PET), non-axiallystretched polypropylene (CPP), acid-modified polypropylene, ionomers,and ON.

The battery lid 4 having a terminal part to be connected to the positiveelectrode terminal 21 and the negative electrode terminal 22 which arelead out from the same side face of the battery cell 3 and plugging theopening 5 of the battery can 2 is configured to have a holder 30 forinserting and holding the positive electrode tab 31 and the negativeelectrode tab 32 which are connected to the positive electrode terminal21 and the negative electrode terminal 22, respectively, the substrate35 provided with the positive electrode terminal board 33 and thenegative electrode terminal board 34 which are connected to the positiveelectrode tab 31 and the negative electrode tab 32, respectively, andthe top cover 36 which sandwiches the holder 30 together with thesubstrate 35 and which is engaged with the opening 5 of the battery can2 and is manufactured by integrally assembling the folder 30, thesubstrate 35 and the top cover 36 as illustrated in FIG. 3.

The holder 30 is a component as formed in a substantially trapezoidalflat plate shape such that an edge in each side of the short sides isformed in a circular arc shape, which is prepared by mold forming asynthetic resin in substantially the same shape as the opening 5 of thebattery can 2. In this holder 30, one pair of insertion holes 41, 42through which the positive electrode tab 31 and the negative electrodetab 32 are inserted, respectively are formed in the vicinity of the sidefaces of the sides of the short sides, and by inserting and holding thepositive electrode tab 31 and the negative electrode tab 32 in theinsertion holes 41, 42, respectively, it is devised to position thepositive electrode tab 31 and the negative electrode tab 32 and also toprevent falling of the secondary battery 1 or position deviation ascaused following the vibration or the like. Accordingly, the positivetab 31 and the negative electrode tab 32 are able to prevent a situationthat welding between the positive electrode terminal 21 and the negativeelectrode terminal 22 comes out due to falling or position deviation ascaused following the vibration or the like.

The positive electrode tab 31 and the negative electrode tab 32 areprovided for the purpose of connecting the positive electrode terminal21 and the negative electrode terminal 22 which are lead out from thebattery cell 3 to the positive electrode terminal board 33 and thenegative electrode terminal board 34 as provided in the substrate 35which becomes an electrode terminal of the secondary battery 1, and wheninserted and supported in the holder 30, one ends 31 a, 32 a areextended to the side of the battery cell 3, whereas the other ends 31 b,32 b are extended and held in the side of the substrate 35. In thesepositive electrode tab 31 and negative electrode tab 32, by using nickel(Ni), the one ends 31 a, 32 a are disposed on the positive electrodeterminal 21 and the negative electrode terminal 22, respectively, theother ends 31 b, 32 b are disposed on the positive electrode terminalboard 33 and the negative electrode terminal board 34 as provided on thesubstrate 35, respectively, and four points are then welded collectivelyby spot welding. This is because since the positive electrode terminal21 is formed by using aluminum (Al), if the positive electrode terminal21 is welded directly to the positive electrode terminal board 33, thealuminum is molten so that the connection cannot be achieved.Accordingly, by mediating the positive electrode tab 31 and the negativeelectrode tab 32 and carrying out welding from the upper side, thepositive electrode terminal 21 is connected to the positive electrodeterminal board 33, and the negative electrode terminal 22 is connectedto the negative electrode terminal board 34.

Furthermore, as illustrate in FIGS. 13A and 13B, in the respective oneends 31 a, 32 a of the positive electrode tab 31 and the negativeelectrode tab 32, folding parts 39, 40 in which tip edges thereof arefolded towards the face in the opposite side to the contact face cominginto contact with the positive electrode terminal 21 and the negativeelectrode terminal 22 are formed. In the folding parts 39, 40, asillustrated in FIG. 14, the positive electrode tab 31 and the negativeelectrode tab 32 each has a thickness of 0.1 mm, whereas the tip thereofis folded in a height of about 0.3 mm. In this way, by folding the tipside, the positive electrode tab 31 and the negative electrode tab 32are each made to stand up in a circular arc shape and joined with thepositive electrode terminal 21 and the negative electrode terminal 22,respectively as described later. Thereafter, when a joining part 50 isfolded, even in the case where the tip comes into contact with thepositive electrode terminal 21 or the negative electrode terminal 22, itis possible to prevent the generation of a situation that the positiveelectrode terminal 21 or the negative electrode terminal 22 is damagedor cut.

Incidentally, an earth 43 for discharging an electric charge as chargedon the battery can 2 is connected to the negative electrode tab 32. Whenthe earth 43 is supported by the holder 30, one end thereof can beconnected to the negative electrode tab 32, whereas the other end can bebrought into contact with the inner surface of the battery can 2. Inthis way, even in the case where an electric charge is charged on themetallic battery can 2, the electric charge can be discharged into thenegative electrode tab 32 through the earth 43 so that there is nopossibility for causing an erroneous operation of a microcomputer withinthe secondary battery 1 or an electronic appliance having the secondarybattery 1 installed therein due to the electric charge as charged on thebattery can 2. Incidentally, the earth may be connected to the substrate35, thereby discharging an electric charge into the negative electrodetab 32 through the substrate 35.

Furthermore, on upper and lower faces 30 a, 30 b of the holder 30,plural coupling projections 44 which are inserted and engaged incoupling holes 46 as provided on the top cover 36 are intermittentlyformed over the longitudinal direction. When the coupling projections 44are engaged in the coupling holes 46, the holder 30 is coupling with thetop cover 36, thereby sandwiching the substrate 35.

The substrate 35 is a rigid substrate on which a circuit pattern forsupplying an electric current flowing from the battery cell 3 into anelectronic appliance via the terminal boards 33, 34 is formed andmounted with the positive electrode terminal board 33 and the negativeelectrode terminal board 34 which are welded to the other ends 31 b, 32b of the positive electrode tab 31 and the negative electrode tab 32,respectively. The positive electrode terminal board 33 and the negativeelectrode terminal board 34 are connected to the positive electrodeterminal part 37 and the negative electrode terminal part 38,respectively as formed on the face in the opposite side to the mountingface. Further, in the substrate 35, the positive electrode terminal part37 and the negative electrode terminal part 38 are faced outwardly viathe terminal holes 48 as provided on the top cover 36 and brought intocontact with the electrode terminals as provided in the side of thedigital still camera 10 or the battery charger 80.

The positive electrode terminal part 37 and the negative electrodeterminal part 38 are formed in a different arrangement from each otherdepending upon the function of the secondary battery 1. The reasons forthis are as follows. In the secondary battery 1 which is used in variouselectronic appliances, there is some case where nevertheless theexternal shape is identical with respect to the battery can 2 or thebattery lid 4, by making the battery capacity different depending uponan electronic appliance to be used, or by making a compatible electronicappliance different, plural types of the secondary batteries 1 which areincompatible with each other are provided. Furthermore, there is somecase where there are provided a plural number of the secondary batteries1 having a different function from each other such as a combination of atype provided with a residual battery life display part such as an LEDdisplay part or a liquid crystal display part and a residual batterylife display button, thereby bringing a residual battery life displayfunction and a type not having such a residual battery life displayfunction; and a combination of a type which is able to achieve quickrecharge and a type which is not able to achieve quick recharge.

However, since the external shape of the secondary battery 1 isidentical in all types having any function, there is some possibilitythat the secondary battery 1 is installed in an incompatible electronicappliance. Then, by making the arrangement of the positive electrodeterminal part 37 and the negative electrode terminal part 38 differentfor every function and similarly making the arrangement of electrodeterminals of a compatible electronic appliance different, it becomespossible to prevent any trouble as caused due to erroneous installationof the secondary battery.

Concretely, the positive electrode terminal part 37 and the negativeelectrode terminal part 38 are arranged in a position of substantialpoint symmetry for every function. For example, in a secondary battery1A having a battery capacity of 760 mAh as illustrated in FIG. 15A and asecondary battery 1B having a high battery capacity of 830 mAh asillustrated in FIG. 15B, the positive electrode terminal part 37 and thenegative electrode terminal part 38 are arranged in a position ofsubstantial point symmetry as rotated through 180 degrees. Incidentally,the positive electrode terminal part 37 and the negative electrodeterminal part 38 may be arranged in a position of bilateral symmetry forevery function as illustrated in FIGS. 16A and 16B. Furthermore, thearrangement shape of substantial point symmetry can be properlyselected.

In this way, by making the arrangement of the positive electrodeterminal part 37 and the negative electrode terminal part 38 differentdepending upon the function of the secondary battery 1 and making thearrangement of electrode terminals of an electronic appliancecorresponding to the function different, even in the case where thesecondary battery 1 is installed in an incompatible electronicappliance, since the electrode terminals in the electronic applianceside do not come into contact with the electrode terminals in the sideof the secondary battery 1, it is possible to prevent any trouble ascaused due to erroneous installation of the incompatible secondarybattery 1.

In the substrate 35, a circuit pattern and a land are formed by etchingwith a copper foil as stuck on an insulating substrate or the like, andthe positive electrode terminal board 33 and the negative electrodeterminal board 34 are mounted on the land by reflow soldering. Asdescribed previously, the positive electrode terminal board 33 and thenegative electrode terminal board 34 are soldered on the positive tab 31and the negative tab 32 together with the positive electrode terminal 21and the negative electrode terminal 22, respectively. Furthermore, thepositive electrode terminal part 37 and the negative electrode terminalpart 38 are formed on the land as formed in a prescribed place bygilding or the like.

Incidentally, if desired, the substrate 35 may be provided with aheat-sensitive element such as PTC (positive temperature coefficient)for detecting the temperature of the secondary battery 1 to achievecharge control or safety control. By providing a heat-sensitive element,when the temperature is elevated, the secondary battery 1 is able toshut and control an input/output circuit.

The top cover 36 which sandwiches the substrate 35 together with theholder 30 is a component in a substantially trapezoidal flat plate shapesuch that an edge in each side of the short sides is formed in acircular arc shape, which is prepared by mold forming a synthetic resinin substantially the same shape as the opening 5 of the battery can 2.In the top cover 36, on an upper face 36 a in the side of the short sideand a lower face 36 b in the side of the long side, plural couplingholes 46 in which plural coupling projections 44 as projected on theholder 30 are inserted and engaged are intermittently formedcorresponding to the coupling projections 44. Furthermore, in the topcover 36, the plural engagement convexes 47 which are engaged with theengagement holes 6 as formed in the periphery of the opening 5 of thebattery can 2 are formed on the upper face 36 a and the lower face 36 b.Further, when the top cover 36 is inserted into the battery can 2 fromthe opening 5 in such a manner that the upper face 36 a and the lowerface 36 b are slightly warped, the engagement convexes 47 are engagedwith the engagement holes 6 and assembled in the battery can 2.

Furthermore, in the top cover 36, the terminal holes 48 from which thepositive electrode terminal part 37 and the negative electrode terminalpart 38 as formed in the substrate 35 are faced outwardly are perforatedon the front face 36 c, and the positive electrode terminal part 37 andthe negative electrode terminal part 38 are brought into contact withthe electrode terminals in the side of an electronic appliance such asthe digital still camera 10 or the battery charger 80 via the terminalholes 48. Incidentally, the terminal hole 48 is, for example, providedin three places depending upon the terminal part as formed in thesubstrate 35 and can be made to work for a positive electrode terminal,a negative electrode terminal and for a terminal for information such asresidual battery life, respectively. Incidentally, the number of theterminal holes 48 can be properly increased or decreased depending uponthe terminal part as provided in the substrate 35.

When the positive electrode terminal 21 and the negative electrodeterminal 22 of the battery cell 3 are connected to the positiveelectrode terminal board 33 and the negative electrode terminal board 34of the substrate 35 via the positive electrode tab 31 and the negativeelectrode tab 32 as held in the holder 30, respectively and the couplingprojections 44 of the holder 30 are then inserted into the couplingholes 46, the top cover 36 is coupled with the holder 30 whilesandwiching the substrate 35 therebetween, thereby forming the batterylid 4. Thereafter, when the engagement convexes 47 of the top cover 36are engaged with the engagement holes 6 as formed in the periphery ofthe opening 5 of the battery can 2, the battery lid 4 is assembled inthe battery can 2, thereby forming the secondary battery 1.

Incidentally, in the top cover 36, as illustrated in FIGS. 17A, 17B and17C, in the case where it is externally attached in a battery installingpart as formed in the casing of an electronic appliance separately fromthe battery accommodating part 12 on the front face 36 c or in the casewhere it is installed in a battery installing part of the batterycharger 80, engagement parts 79 which are engaged with engagementprojections 78 as projected in the battery installing part of theelectronic appliance or the battery charger may be formed. In thesecondary battery 1, as illustrated in FIG. 6, the battery can 2 isinstalled while engaging the engagement parts 79 with the engagementprojections 78. The secondary battery 1 is formed such that the batterycan 2 is attached while the engagement parts 79 are engaged with theengagement projections 78 as shown in FIG. 6. The engagement parts 79can be easily formed in mold forming the top cover 36. Incidentally,FIG. 17A shows an example in which the engagement parts 79 are formed ina concave form in the both ends of the front face 36 c of the top cover36; FIG. 17B shows an example in which the both ends of the engagementparts 79 in a concave form are notched; and FIG. 17C shows an example inwhich engagement concaves are provided in the battery installing part,and convex engagement parts 79 provided with a shape corresponding tothe engagement convexes are formed in the top cover 36 of the secondarybattery 1.

Incidentally, in this specification, with respect to the secondarybattery 1, the principal face in the side of the short side of thebattery can 2 is referred to as the upper face 1 a of the secondarybattery 1; the principal face on the side of the long side of thebattery can 2 is referred to as the lower face 1 b of the secondarybattery 1; the front face 36 c of the top cover 36 is referred to as thefront face 1 c of the secondary battery 1; and the bottom face part 7 ofthe battery can 2 is referred to as the back face 1 d of the secondarybattery 1.

Next, the manufacturing process of the secondary battery 1 will bedescribed below with reference to FIGS. 18A to 18L. First of all, asillustrated in FIG. 18A, the battery cell 3 and the substrate 35 arearranged in a jig, the details of which are omitted. Incidentally, atthis time, the battery cell 3 is cut along the overlap width 28 of thecell aggregate 27 and the overlap width 28 is folded along the side faceof the battery cell 3 into a substantially trapezoidal shape withrespect to the cross section thereof, thereby making it easy forhandling; and as described later, in accommodating in the battery can 2,when the folded overlap width 28 is arranged between the side face ofthe battery can 2 and the battery cell 3, it functions as a buffermember. Furthermore, in the substrate 35, a prescribed circuit patternand the positive electrode terminal part 37 and the negative electrodeterminal part 38 are formed, and the positive electrode terminal board33 and the negative electrode terminal board 34 are reflow soldered.

Incidentally, with respect to the formation of the battery cell 3, inaddition to the case of forming the cell aggregate 27 and cutting italong the overlap width 28, a sealing sheet may be joined with anaccommodating sheet having the battery element 20 accommodated thereinfor every individual battery cell.

The battery cell 3 is arranged in such a manner that the joining facebetween the accommodating sheet 24 from which the positive electrodeterminal 21 and the negative electrode terminal 22 are lead out and thatthe sealing sheet 26 are faced upwardly and that the bottom part of theaccommodating concave 25 is faced downwardly. That is, the battery cell3 in a substantially trapezoidal form with respect to the cross sectionthereof is arranged in such a manner that the side of the short side isfaced downwardly and that the side of the long side from which thepositive electrode terminal 21 and the negative electrode terminal 22are lead out is faced upwardly. Furthermore, the battery cell 3 isarranged in such a manner that the lead-out face 3 a from which thepositive electrode terminal 21 and the negative electrode terminal 22are lead out is faced towards the side of the substrate 35. Thesubstrate 35 is arranged in such a manner that the mounting face onwhich the positive electrode terminal board 33 and the negativeelectrode terminal board 34 are mounted is faced upwardly and that theside of the short side in a substantially trapezoidal shape is facedtowards the side of the lead-out face 3 a of the battery cell 3.

Next, as illustrated in FIG. 18B, in the holder 30, the positiveelectrode tab 31 and the negative electrode tab 32 are inserted in andheld by the insertion holes 41, 42. Furthermore, at this time, the earth43 is also installed in the holder 30. Next, as illustrated in FIG. 18C,by installing this holder 30 in a jig, the holder 30 is arranged betweenthe battery cell 3 and the substrate 35. In the holder 30, the side ofthe short side in a substantially trapezoidal shape in which thepositive electrode tab 31 and the negative electrode tab 32 are held isfaced downwardly and positioned with the short side of the substrate 35.Furthermore, in the holder 30, the one end 31 a of the positiveelectrode tab 31 is superposed on the positive electrode terminal 21 ofthe battery cell 3, and the one end 32 a of the negative electrode tab32 is superposed on the negative electrode terminal 22. Moreover, theother end 31 b of the positive electrode tab 31 is superposed on thepositive electrode terminal board 33 of the substrate 35, and the otherend 32 b of the negative electrode tab 32 is superposed on the negativeelectrode terminal board 34. In this way, the positive electrodeterminal 21 and the negative electrode terminal 22 of the battery cell3, the positive electrode tab 31 and the negative electrode tab 32 ofthe holder 30, and the positive electrode terminal board 33 and thenegative electrode terminal board 34 of the substrate 35 are placed onsubstantially the same plane (see FIG. 19).

Next, four places of the one end 31 a and the other end 31 b of thepositive electrode tab 31 and the one end 32 a and the other end 32 b ofthe negative electrode tab 32 are welded from the upper side,respectively, thereby joining the positive electrode terminal 21 of thebattery cell 3 to the one end 31 a of the positive electrode tab 31, thenegative electrode terminal 22 to the one end 32 a of the negative tab32, the positive electrode terminal board 33 of the substrate 35 to theother end 31 b of the positive electrode tab 31, and the negativeelectrode terminal board 34 to the other end 32 b of the negativeelectrode tab 32, respectively. Here, though aluminum (Al) is used forthe positive electrode terminal 21, since the positive electrodeterminal 21 is welded from the upper side of the positive electrode tab31 made of nickel, the both can be surely joined to each other withoutthe generation of dissolution by heat.

Next, as illustrated in FIG. 18D, the substrate 35 is made to stand up,thereby superposing the holder 30 thereon. At this time, in therespective other ends 31 b, 32 b of the positive electrode tab 31 andthe negative electrode tab 32 which are held by the holder 30, the baseend parts which are projected from the insertion holes 41, 42 in theside of the substrate 35 are folded along the standing-up direction ofthe substrate 35.

Next, as illustrated in FIG. 18E, insulating paper 51 is stuck so as tocover the joining part 50 among the positive electrode terminal 21 andthe negative electrode terminal 22 and the one end 31 a of the positiveelectrode tab 31 and the one end 32 a of the negative electrode tab 32.The insulating paper 51 not only reinforces the joining part 50 amongthe positive and negative electrode terminals 21, 22 and the positiveand negative electrode tabs 31, 32 but also prevents the generation of ashort circuit due to the contact between the metallic battery can 2 andthe joining part 50 and the generation of a short circuit between thepositive electrode and the negative electrode due to deformation of thepositive electrode tab 31 and the negative electrode tab 32. In theinsulating paper 51, an adhesive layer is formed in the side of oneface, and by folding the insulating paper 51 while sandwiching thejoining part 50 as illustrated in FIG. 18F, the adhesive layers arestuck to each other, thereby achieving sticking.

Next, as illustrated in FIG. 18G, the holder 30 is coupled with the topcover 36, thereby forming the battery lid 4. Thereafter, as illustratedin FIG. 18H and FIGS. 13A and 13B, the joining part 50 on which theinsulating paper 51 is stuck among the positive electrode terminal 21and the negative electrode terminal 22 and the one end 31 a of thepositive electrode tab 31 and the one end 32 a of the negative electrodetab 32 is folded in a substantially S-shaped form such that the lead-outface 3 a of the battery cell 3 and the battery lid 4 are faced at eachother. In this way, by accommodating the joining part 50 in a curvedstate in the battery can 2, even in the case where an impact is appliedbetween the battery cell 3 and the battery lid 4 by falling, vibration,or the like, a load of the impact is absorbed by the joining part 50 asfolded in a substantially S-shaped from and accommodated so that it ispossible to prevent separation or breakage of the positive electrodeterminal 21 and the negative electrode terminal 22 and the positiveelectrode tab 31 and the negative electrode tab 32 from occurring (seeFIGS. 13A and 13B).

Next, as illustrated in FIG. 18I, in the battery cell 3, an elasticmember 55 having a slight thickness and having an adhesive layer formedon the both sides thereof is stuck on the insertion end face 3 b intothe battery can 2. This elastic member 55 not only makes the batterycell 3 fix inside the battery can 2, thereby preventing unsteadiness butalso absorbs an impact which is applied to the battery cell 3. Examplesof the elastic member 55 include a pressure sensitive adhesive doublecoated tape using a polyurethane foam as a base material. The insertionend face 3 b of the battery cell 3 is not formed in a flat shape and isa face in which the shape thereof is liable to be scattered. However,the scattering is absorbed by the elastic member 55 so that the batterycell 3 can be surely adhered to the inside of the battery can 2.Furthermore, the elastic member 55 can absorb an impact which is appliedto the battery cell 3 due to falling, vibration, or the like or canreduce a load to the joining part 50 due to heat expansion of thebattery cell 3. Thus, the elastic member 55 is able to preventseparation of the positive electrode terminal 21 and the negativeelectrode terminal 22 and the positive electrode tab 31 and the negativeelectrode tab 32 from occurring together with the foregoing insulatingpaper 51.

When the elastic member 55 is formed in a substantially rectangularshape depending upon the shape of the insertion end face 3 b of thebattery cell 3 and arranged in the both end parts in a longitudinaldirection along the side face of the battery cell 3, an insulating film56 for insulating the overlap width 28 of the battery cell 3 from thebattery can 2 is stuck. That is, the accommodating sheet 24 and thesealing sheet 26 which configure the pack 23 of the battery cell 3 areeach a sheet in which the polypropylene (PP) layer 52, the aluminum (Al)layer 53, and the nylon layer 54 are stacked in this order from theinside as described previously. When cut along the overlap width 28, therespective layers which configure the sheet are exposed outwardly on thecut face. Among them, when the aluminum layer 53 comes into directcontact with the metallic battery can 2, in the case where the batterycan 2 is charged, the aluminum layer 53 becomes a genitive electrode.When the polypropylene layer 52 further has a hole due to some cause,the aluminum layer 53 has a hole by electrolytic corrosion. Further,there is some possibility that when moisture invades from the hole ofthe pack 23, the battery cell 3 is expanded. Then, by arranging theinsulating film 56 along the cut face of the battery cell 3, it isdevised to achieve insulation between the battery can 2 and the cut faceof the pack 23, thereby preventing the expansion of the battery cell 3due to moisture absorption of the battery element 20.

The insulating film 56 is a longitudinal film as formed depending uponthe side face of the battery cell 3, one end of which is stuck to eachof the end parts of the elastic member 55. As illustrated in FIG. 20,when the battery cell 3 is inserted into the battery can 2 from theinsertion end face 3 b, the insulating film 56 is folded along the sideface of the battery cell 3 by a side edge part of the opening 5 of thebattery can 2 and arranged between the cut face of the overlap width 28as folded on the side face of the battery cell 3 and the side face ofthe battery can 2. In this way, it is possible to prevent the contactbetween the aluminum layer 53 as exposed on the cut face of the overlapwidth 28 and the battery can 2.

Next, as illustrated in FIG. 18J, the battery cell 3 is inserted intothe battery can 2, and the opening 5 of the battery can 2 is plugged bythe battery lid 4. At this time, the battery cell 3 is inserted in sucha manner that the side of the short side and the side of the long sideof the substantially trapezoidal shape with respect to the cross sectionthereof are made adaptive with the side of the short side and the sideof the long side of the battery can 2 as formed similarly substantiallytrapezoidal shape with respect to the cross section thereof. In thisway, a space within the battery can 2 can be effectively utilized sothat a prescribed clearance is provided between the battery can 2 andthe battery cell 3. As illustrated in FIGS. 21A to 21C, this clearancebecomes a margin in the case where the battery cell 3 is expanded byheat or the like so that an excessive load to the joining part 50 ordeformation of the battery can 2 as caused due to the expansion of thebattery cell 3 can be avoided. Incidentally, FIG. 21A shows the casewhere the both principal faces of the battery cell 3 are equallyexpanded; and each of FIGS. 21B and 21C schematically shows the casewhere the both principal faces of the battery cell 3 are unequallyexpanded.

Furthermore, in the case where the direction of the battery cell 3 isreversed, since the edge of each side of the long sides of the batterycell 3 interferes with the edge in a circular arc shape as formed ineach side of the short sides of the battery can 2, thereby preventingthe invasion, it is possible to prevent erroneous insertion fromoccurring.

As illustrated in FIG. 20, when the battery cell 3 is inserted, theinsulating film 56 is arranged along the side face of the battery cell 3by the side edge of the opening 5 of the battery can 2. Furthermore, thebattery cell 3 is adhered to the bottom face part of the battery can 2by the elastic member 55 as stuck on the insertion end face 3 b.Subsequent to the insertion of the battery cell 3, the engagementconvexes 47 as projected on the top cover 36 invade into the opening 5while being warped and are then engaged with the engagement holes 6. Inthis way, the battery lid 4 is assembled in the opening 5 of the batterycan 2.

Furthermore, when the battery lid 4 is assembled in the battery can 2,the joining part 50 among the positive electrode terminal 21 and thenegative electrode terminal 22 and the positive electrode tab 31 and thenegative electrode tab 32 is arranged in a curved state in asubstantially S-shaped form between the battery cell 3 and the holder30.

Next, as illustrated in FIG. 18K, the external label 15 is stuck to theperiphery of the battery can 2. The external label 15 is stuck such thatthe principal face part 16 winds the outer periphery of the battery can2; that the first winding part 17 winds a region exclusive of the bothend parts in the longitudinal direction of the bottom face part 7; andthat the second winding part 18 winds a region exclusive of the terminalhole 48 as formed in the top cover 36 of the battery lid 4. Finally, asillustrated in FIG. 18L, the information label 49 on which a variety ofinformation of the secondary battery 1 is described is stuck in theprincipal face part of the side of the long sides of the battery can 2to which the external label 15 has been stuck, thereby completing thesecond battery 1.

According to the secondary battery 1 having the foregoing configuration,by mutually assembling the metallic battery can 2 and the mold formedbattery lid 4, assembling can be easily achieved. Furthermore, byforming the battery can 2 by deep drawing using a metallic material,slimming and insurance of strength can be achieved at the same time sothat it is possible to provide a secondary battery which is able to meetthe demands for an electronic appliance such as downsizing, slimming andlightweight. In addition, the external shape of the engagement hole 8 orthe engagement part 79 which becomes the installing end in installingthe secondary battery in a battery installing part of an electronicappliance can be easily formed by processing the metallic battery can 2or mold forming the battery lid 4 made of a synthetic resin.

Furthermore, in the secondary battery 1, when the battery can 2 and thebattery lid 4 are formed in a substantial trapezoidal shape with respectto the cross section thereof in which the edge of each side of the shortsides is formed in a circular arc shape and the battery accommodatingpart 12 in the side of the digital still camera 10 is formed in the sameshape, in the case where the insertion face is reversed in the back andfront, the edges of the battery accommodating part 12 and the edges ofthe secondary battery 1 interfere with each other, thereby inhibitingthe insertion. Thus, it is possible to surely prevent erroneousinsertion.

Furthermore, in the battery can 2, it is possible to provide the canbottom electrode 57 in the bottom face part 7 to which the externallabel 15 is not stuck, thereby using it as a negative electrode or anearth electrode. Moreover, when the both ends of the bottom face part 7to which the external label 15 is not stuck are an engagement part withwhich the engagement member 19 as provided in the side of an electronicappliance is engaged, even when rubbed repeatedly by the engagementmember 19, a situation such as breakage or separation of the externallabel 15 can be prevented from occurring. Moreover, by forming asticking region of the external label 15 which is stuck in the bottomface part 7 of the battery can 2 into a region corresponding to aposition of each of the positive electrode terminal part 37 and thenegative electrode terminal part 38 of the secondary battery 1, evenwhen the secondary battery 1 is installed in an erroneous direction ofan electronic appliance such as the digital still camera 10 or thebattery charger 80, since the insulating external label as stuck in thebottom face part 7 of the secondary battery 1 comes into contact withthe side of the digital still camera 10 or the battery charger 80 asprovided corresponding to the position of each of the positive electrodeterminal part 37 and the negative electrode terminal part 38, it ispossible to prevent a short circuit due to direct contact of the bottomface part 7 from occurring. In addition, by winding the external label15 in a region exclusive of a forming region of each of the positiveelectrode terminal part 37 and the negative electrode terminal part 38of the battery lid 4, it is possible to enhance the assembling strengthbetween the battery can 2 and the battery lid 4. Accordingly, since itis not required to protrude the engagement convexes 47 as formed on thebattery lid 4 which is engaged with the battery can 2 in the upper faceside of the battery can 2 from the engagement hole 6, the assemblingstrength can be ensured without hindering the flatness or appearance ofthe second battery 1.

In addition, in the secondary battery 1, by making the position of eachof the positive electrode terminal part 37 and the negative electrodeterminal part 38 which are formed on the battery lid 4 differentdepending upon a difference in the function such as battery capacitywhile making the battery can 2 and the battery lid 4 have the sameshape, even in the case where the secondary battery 1 of an incompatibletype is installed in the incompatible digital still camera 10,conductance does not occur between the electrode terminals so that atrouble can be prevented from occurring.

In addition, in the secondary battery 1, when the battery can 2 and thebattery cell 3 are formed in a substantial trapezoidal shape withrespect to the cross section thereof in which the edge line of each sideof the short sides is formed in a circular arc shape, it is possible toprevent erroneous insertion of the battery cell 3 into the battery can 2and to effectively utilize a space within the battery can 2. In thisway, it is possible to provide a clearance which when the battery cell 3is heat expanded, becomes a margin between the battery cell 3 and aninner wall of the battery can 2. Accordingly, even in the case where thebattery cell 3 is heat expanded, the battery can 2 does not causedistortion, or an excessive load is not applied to the joining part 50among the positive electrode terminal 21 and the negative electrodeterminal 22 and the positive electrode tab 31 and the negative electrodetab 32.

In addition, in the secondary battery 1, the battery lid 4 is configuredto have the holder 30 for devising to position and fix the positiveelectrode tab 31 and the negative electrode tab 32, the substrate 35provided with the positive electrode terminal part 37 and the negativeelectrode terminal part 38, and the top cover 36 for sandwiching thesubstrate 35 together with the holder 30. In this way, in the holder 30,by devising to position the positive electrode tab 31 and the negativeelectrode tab 32 and holding them, it is positive to easily achievewelding with the positive electrode terminal 21 and the negativeelectrode terminal 22 or with the positive electrode terminal board 33and the negative electrode germinal board 34. Also, even in the casewhere an impact is applied by falling or vibration of the secondarybattery 1, or the like, it is possible to prevent a situation that thewelded portion between the positive electrode tab 31 and the negativeelectrode tab 32 comes out.

In addition, in the secondary battery 1, since the battery can 2 isinstalled on the insertion end face 3 b of the battery cell 3 throughthe elastic member 55, not only unsteadiness of the battery cell 3within the battery can 2 can be prevented, but also an impact due tofalling or vibration of the battery can 2, or the like can be absorbed,thereby preventing the impact to apply to the joining part 50.Furthermore, by folding the overlap width 28 along the side face andthen inserting the battery cell 3 into the battery can 2, it is possibleto make the folded overlap width function as a buffer member between thebattery cell 3 and the battery can 2.

In addition, in the secondary battery 1, by sticking the insulating film56 on the elastic member 55, when the battery cell 3 is inserted intothe battery can 2, the insulating film 56 is arranged along the sideface of the battery cell 3 while being guided on the side face of theopening 5 of the battery can 2 to cover the aluminum layer 53 of thepack 23 which is exposed on the cut face of the overlap width 28,thereby enabling it to devise to insulate from the inner wall of thebattery can 2. Accordingly, even in the case where the metallic batterycan 2 is charged, the battery can 2 and the aluminum layer 53 of thepack 23 come in direct contact with each other to become the negativeelectrode, and it is possible to prevent a phenomenon in which thepolypropylene layer 52 has a hole due to some cause, thereby causingelectrolytic corrosion, the pack 23 has a hole, and moisture invadesfrom this hole, thereby causing expansion of the battery cell 3.

In addition, in the secondary battery 1, since the insulating paper 51is stuck to the joining part 50 among the positive electrode terminal 21and the negative electrode terminal 22 and the positive electrode tab 31and the negative electrode tab 32, not only it is possible to reinforcethe joining part 50, but also it is possible to prevent the generationof a short circuit as caused due to the contact with the metallicbattery can 2. Furthermore, by accommodating this joining part 50 intothe battery can 2 while being curved in a substantially S-shaped form,even in the case where an impact is applied between the battery cell 3and the battery lid 4 due to falling or vibration of the secondarybattery 1 or the like, the joining part 50 which has been folded in asubstantially S-shaped form and accommodated is warped so that a load ofthe impact is absorbed, thereby preventing the separation of thepositive electrode terminal 21 and the negative electrode terminal 22and the positive electrode tab 31 and the negative electrode tab 32 fromoccurring.

Incidentally, as described previously, in the secondary battery 1 towhich the invention is applied, the battery cell 3 is adhered to theinside of the battery can 2 via the elastic member 55. However, asillustrated in FIGS. 22A to 22C, there may be employed a configurationin which prior to the insertion of the battery cell 3, an adhesive 58 iscoated on one principal face within the battery can 2, and the adhesive58 is spread on the one principal face within the battery can 2 by thebattery cell 3 to be inserted into the battery can 2, thereby adheringthe battery cell 3 to the battery can 2. By employing such aconfiguration, the battery cell 3 can be fixed in the battery can 2,thereby preventing unsteadiness of the battery cell 3 within the batterycan 2 as caused by falling or vibration of the secondary battery 1 orthe like. Accordingly, an excessive load is not applied to the joiningpart 50 among the positive electrode terminal 21 and the negativeelectrode terminal 22 and the positive electrode tab 31 and the negativeelectrode tab 32 so that it is possible to prevent the separation of thepositive electrode terminal 21 and the negative electrode terminal 22and the positive electrode tab 31 and the negative electrode tab 32.

Furthermore, by fixing the battery cell 3 inside the battery can 2 byusing the adhesive 58, it is possible to effectively utilize a spacewithin the battery can 2, and it is possible to form a prescribedclearance between the principal face of the battery cell 3 in theopposite side to the adhesive face and an inner wall of the battery can2 opposing to the foregoing principal face. Accordingly, as illustratedin FIG. 23, even in the case where the battery cell 3 is heat expanded,since a margin against the volume exposition of the battery cell 3 isensured by the clearance, it is possible to prevent a situation thatdistortion is generated in the battery can 2 or that an excessive loadis applied to the joining part 50.

Furthermore, in the secondary battery to which the invention is applied,there may be employed not only a configuration in which the singlebattery cell 3 is inserted into the battery can 2 but also aconfiguration as illustrated in FIG. 24, in which a cell stack 61 havingplural battery cells 3 stacked therein is formed and inserted into asingle battery can 62. A secondary battery 60 which is configured toaccommodate the cell stack 61 therein will be described below.Incidentally, with respect to the same members as in the foregoingsecondary battery 1, the same symbols are given, and details thereof areomitted.

In the cell stack 61, plural battery cells 3 are stacked in such amanner that lead-out faces 3 a from which a positive electrode terminal21 and a negative electrode terminal 22 are lead out are faced towardsthe same direction, and if desired, the respective battery cells 3 maybe adhered to each other. In the cell stack 61, the positive electrodeterminal 21 and the negative electrode terminal 22 as lead out from eachof the battery cells 3 are welded with a positive electrode terminalboard 66 and a negative electrode terminal board 67 of a substrate 65which configures a battery lid 64, respectively.

In the cell stack 61, by folding the foregoing cell aggregate 27 alongan overlap width 28, the battery cells 3 are stacked. The battery cell 3may be stacked in two stages as illustrated in FIG. 24 or may be stackedin three stages as illustrate in FIG. 25. In the case where the batterycell 3 is stacked in three stages, as illustrate in FIG. 26, the cellaggregate 27 is formed such that widths W₁ and W₂ of the overlap widths28 to be provided between the respective battery cells 3 are madedifferent. In the secondary battery 60, the battery capacity and thevoltage can be freely set up by the stacking number of the battery cell3 and the wiring among the respective battery cells 3.

Incidentally, the cell stack 61 may be formed by individually cuttingout the battery cell 3 from the cell aggregate 27 and stacking thebattery cells such that the lead-out faces 3 a are faced towards thesame direction.

In the substrate 65, a positive electrode terminal board 66 and anegative electrode terminal board 67 with which a positive electrodeterminal 21 and a negative electrode terminal 22 as lead out from eachof the battery cells 3 are welded, and a positive electrode terminalpart 71 and a negative electrode terminal part 72 which are connected tothe positive electrode terminal board 66 and the negative electrodeterminal board 67, respectively by a circuit pattern and which are facedoutwardly via a terminal hole 70 as formed on a top cover 69 are formed.

In the secondary battery 60, the stacked battery cells 3 can be set upby a circuit pattern of the substrate 65 such that they are connected inseries or in parallel. Such a circuit pattern is formed by an etchingprocess with a copper foil, a printing process with a conductive paste,or the like. Furthermore, the positive electrode terminal board 66 andthe negative electrode terminal board 67 are mounted on the land byreflow soldering. The positive electrode terminal part 71 and thenegative electrode terminal part 72 are formed on the land as formed ina prescribed place by gilding or the like. Incidentally, likewise theforegoing secondary battery 1, the positive electrode terminal part 71and the negative electrode terminal part 72 may be arranged in adifferent position depending upon a difference in every function such asbattery capacity of the secondary battery 60. The substrate 65 issandwiched by a holder 68 and the top cover 69 and configures a batterylid 64 together with the holder 68 and the top cover 69.

The holder 68 is coupled with the top cover 69 via the substrate 65,thereby sandwiching the substrate 65 together with the top cover 69. Inthis way, the holder 68 receives a pressing pressure which is applied tothe positive electrode terminal part 71 and the negative electrodeterminal part 72 together with the top cover 69, thereby preventing asituation that an excessive load is applied to the positive electrodeterminal part 71 and the negative electrode terminal part 72. Thisholder 68 is prepared by mold forming a synthetic resin in substantiallythe same shape as an opening 63 of the battery can 62. Furthermore, inthe holder 68, on an upper face 68 a and a lower face 68 b, pluralcoupling projections 73 which are engaged in coupling holes 74 as formedon the top cover 69 are intermittently formed.

The top cover 69 which holds the substrate 65 together with the holder68 is a component which is prepared by mold forming a synthetic resin insubstantially the same shape as the opening 63 of the battery can 62 andcan be engaged with the opening 63 closely. In the top cover 69, on anupper face 69 a and a lower face 69 b, plural coupling holes 74 in whichthe plural coupling projections 73 as projected on the holder areinserted and engaged are intermittently formed corresponding to thecoupling projections 73. Furthermore, in the top cover 69, on the upperand lower faces 69 a, 69 b, plural engagement convexes 77 with whichengagement holes 76 as formed in the periphery of the opening 63 of thebattery can 62 are engaged are formed. Further, when the top cover 69 isinserted into the battery can 62 from the opening 63 while the upper andlower faces 69 a, 69 b are slightly warped, the engagement convexes 77are engaged with the engagement holes 76 and assembled in the batterycan 62.

Furthermore, in the top cover 69, terminal holes 70 are projected fromthe front face 69 c such that the positive electrode terminal part 71and the negative electrode terminal part 72 as formed on the substrate65 are faced outwardly, and the positive electrode terminal part 71 andthe negative electrode terminal part 72 are brought into contact with anelectrode terminal in the side of an electronic appliance such as thedigital still camera 10 or the battery charge 80 through the terminalholes 70.

In the top cover 69, after connecting the positive electrode terminal 21and the negative electrode terminal 22 of the battery cell 3 to thepositive electrode terminal board 66 and the negative electrode terminalboard 67 of the substrate 65, respectively, by inserting the couplingprojections 73 of the holder 68 into the coupling holes 74, the topecover 69 is coupled with the holder 68 while sandwiching the substrate65, thereby forming the battery lid 64. Thereafter, when the engagementconvexes 77 of the top cover 69 are engaged with the engagement holes 76as formed in the periphery of the opening 63 of the battery can 62, thebattery lid 64 is assembled in the battery can 62, thereby forming thesecondary battery 60.

The battery can 62 into which the cell stack 61 is inserted is made of ametallic casing in which one face of a substantially flat cube is openedand is formed in a substantially rectangular shape with respect to thecross section thereof depending upon the shape of the cell stack 61. Inthe battery scan 62, the opening 63 for inserting the cell stack 61 isformed only on one face by molding a metallic material such as iron bydeep drawing. By regulating a wall thickness at approximately 0.3 mm,this battery can 62 is formed in a slim shape such that when anaccommodating region of the battery cell 3 is eliminated, its ownthickness is controlled to the utmost; and at the same time, by usingthe metallic material, the battery can 62 can be provided withmechanical strengths against various impacts such as falling, andvibration. The opening 63 is an insertion end from which the cell stack61 is inserted and after insertion of the cell stack 61, is plugged bythe battery lid 64. For that reason, plural engagement holes 76 withwhich engagement convexes 77 as projected on the battery lid 64 areperforated in the periphery of the opening 63. In the engagement holes76, when the battery lid 64 is inserted into the opening 63, theengagement convexes 77 as projected on the battery lid 64 invade intothe opening 63 while being warped and are then engaged with theengagement holes 76. In this way, the battery lid 64 is assembled in thebattery can 62.

Incidentally, likewise the foregoing secondary battery 1, in the batterycan 62, in the case where it is externally attached in a batteryinstalling part of an electronic appliance in the bottom face partopposing to the opening 63 or in the case where it is installed in thebattery installing part of the battery charger 80, engagement holeswhich are engaged with engagement convexes as projected in the batteryinstalling part may be formed. Furthermore, engagement concaves may beprovided in the battery installing part, and engagement convexes may beformed in the bottom face part of the battery can 62. Similarly,likewise the foregoing secondary battery 1, in the top cover 69, in thecase where it is externally attached in a battery installing part of anelectronic appliance in a prescribed place of a front face 69 c or inthe case where it is installed in the battery installing part of thebattery charger 80, concave engagement parts which are engaged withengagement convexes as protected in the battery installing part may beformed. Furthermore, engagement concaves may be provided in the batteryinstalling part, and convex engagement parts may be formed in the frontface 69 c of the top cover 69.

Incidentally, in the battery can 62, likewise the foregoing secondarybattery 1, after connecting it to the battery lid 64, inserting the cellstack 61 and plugging the opening 63 by the battery lid 64, aninsulating external label 15 and an information label 49 in which avariety of information of the secondary battery 60 is described arestuck. The configuration and effect of the external label 15 are thesame as in the case where it is stuck to the foregoing secondary battery1.

Furthermore, the battery can 62 may be formed in a substantiallytrapezoidal shape with respect to the cross section thereof in which theedge line in the direction of short sides is formed in a circular arcshape as illustrate in FIG. 27, in addition to the case where thebattery can 62 is formed in a substantially rectangular shape withrespect to the cross section thereof. By taking such a shape, thesecondary battery 60 can be prevented from erroneous insertion into thebattery installing part of an electronic appliance such as the digitalstill camera 10 or the battery charger 80.

The foregoing secondary battery 60 is manufactured as follows. First ofall, as illustrated in FIG. 28, the cell aggregate 27 is cut in such amanner that two or more of battery cells 3 are continued depending uponthe stacking number of the battery cell 3 and folded along the overlapwidth 28 so as to stack the battery cells 3, thereby forming the cellstack 61.

Next, as illustrated in FIG. 29, the positive electrode terminal 21 andthe negative electrode terminal 22 which are lead out from each of thebattery cells 3 of the cell stack 61 are welded with the positiveelectrode terminal board 66 and the negative electrode terminal board 67as mounted on the substrate 65. Incidentally, in the substrate 65, thecircuit pattern for connecting the respective battery cells 3 in seriesor in parallel and the positive electrode terminal part 71 and thenegative electrode terminal part 72 are formed in advance in a separateprocess, and the positive electrode terminal beard 71 and the negativeelectrode terminal board 72 are mounted; and the substrate 65 issupported by the holder 68.

Next, the holder 68 and the top cover 69 are coupled with each other toform the battery lid 64, and the cell stack 61 is subsequently insertedinto the opening 63 of the battery can 62. At this time, in the cellstack 61, by sticking the elastic member 55 having the insulating film56 provided therein to the insertion end face 3 b of each of the batterycells 3, the pack 23 may devise to achieve insulation from the innerwall of the battery can 62 by the insulating film 56 at the same time ofinserting the battery can 62 or may be fixed to the battery can 62 bythe elastic member 55.

Subsequent to the insertion of the cell stack 61, the battery lid 64 isassembled in the opening 63 of the battery can 62. Thereafter, theexternal label 15 is stuck to the battery can 62. As describedpreviously, the external label 15 becomes a decorative label of thesecondary battery 60 and also devises to achieve insulation of themetallic battery can 62. Furthermore, the external label 15 is providedwith the principal face part 16 for winding the outer periphery of thebattery can 62, the first winding part 17 for winding a region exclusiveof the both end parts in a longitudinal direction of the bottom facepart of the battery can 62, and the second winding part 18 for winding aregion exclusive of the terminal hole 70 as formed in the top cover 69of the battery lid 64.

In this way, in the secondary battery 60, the both ends in the bottomface part of the battery can 62 become an engagement part with which theengagement member as provided in the battery accommodating part of anelectronic appliance. Also, when the external label 15 is stuck so as towind even the battery lid 64, it is possible to ensure an assemblingstrength between the battery lid 64 and the battery can 62 withouthindering the flatness and appearance.

According to the thus configured secondary battery 60, by using the cellstack 61 having plural battery cells 3 stacked therein as the needarises, it is possible to easily obtain a secondary battery with highbattery capacity or a secondary battery with long life. Furthermore, inthe secondary battery 60, since the respective battery cells 3 can beconnected in series or in parallel depending upon the circuit pattern asformed on the substrate, it is possible to devise to achieve highcapacity or long life with ease.

Next, the battery charger 80 for charging the foregoing secondarybattery will be described below. The battery charger 80 is used as abattery charger which is common in plural kinds of secondary batteries 1which are equal in the outer shape but are different in a point that thepositive electrode terminal part 37 and the negative electrode terminalpart 38 which are faced from the front face 1 c are arranged in aposition of substantial point symmetry depending upon a difference in abattery capacity or a compatible electronic appliance, the presence orabsence of a residual battery life display function, or a differencebetween a type which is able to achieve quick recharge and a type whichis not able to achieve quick recharge.

As illustrated in FIG. 30, the battery charger 80 has a battery chargemain body 81, a battery accommodating part in which the secondarybattery 1 is accommodated, an electrode terminal which is arrangedwithin the battery accommodating part 82 and which is brought intocontact with the positive electrode terminal part 37 and the negativeelectrode terminal part 38 of the secondary battery 1, and a transparentpart 84 in which the electrode terminal 83 can be viewed from theoutside of the battery charger main body 81.

As illustrated in FIG. 30, the battery charger main body 81 is, forexample, made of a cube larger than the secondary battery 1, and thebattery accommodating part 82 is formed in a principal face part 81 a.The battery accommodating part 82 is a concave having substantially thesame size as the secondary battery 1; and the electrode terminal 83 isformed in one side wall part 82 a corresponding to the position of thepositive electrode terminal part 37 and the negative electrode terminalpart 38 which are faced outwardly from the terminal holes 48 as providedin the front face 1 c of the secondary battery 1. Furthermore, in thebattery charger main body 81, the transparent part 84 capable ofenhancing the visibility of the electrode terminal 83 is formed from aside wall part 82 a in which the electrode terminal 83 is formed to theprincipal face part 81 a. By providing the transparent part 84, a userof the battery charger 80 can easily view the position of the electrodeterminal 83 from the upper side. Furthermore, in installing thesecondary battery 1 in the battery accommodating part 82, it is possibleto easily confirm that the positive electrode terminal part 37 and thenegative electrode terminal part 38 in the side of the secondary battery1 are connected to the electrode terminal 83 in the side of the batterycharger main body 81 without making a mistake on the insertiondirection. Besides, the battery charger main body 81 is provided with acord for taking in an external power source, a display part fordisplaying the charging state by an LED element or a liquid crystal, andso on, details of which are, however, omitted.

Here, as described previously, the secondary battery 1 which isinstalled in the battery charger 80 is formed in such a manner that thearrangement of the positive electrode terminal part 37 and the negativeelectrode terminal part 38 is made different depending upon thefunction, for example, whether or not it is of a high battery capacitytype, whether or not a residual battery life display function by LED, aliquid crystal, or the like is provided, a difference of a compatibleelectronic appliance, or whether or not quick recharge is possible. Thatis, while the outer shape of the battery can 2 and the battery lid 4which configure the secondary battery 1 is the same regardless of adifference of the function, the positive electrode terminal part 37 andthe negative electrode terminal part 38 which are formed in thesubstrate 35, which configure the battery lid 4, are arranged in aposition of substantial point symmetry depending upon the foregoingevery function. Similarly, the electrode terminal which is provided inthe side of an electronic appliance takes an arrangement correspondingto the arrangement of the positive electrode terminal part 37 and thenegative electrode terminal 38 of the corresponding secondary battery.In this way, even in the case where the secondary battery 1 is installedin an incompatible electronic appliance, since the positive electrodeterminal part 37 and the negative electrode terminal part 38 in the sideof the secondary battery 1 do not come into contact with the electrodeterminal as provided in the side of the electronic appliance, it ispossible to prevent a trouble as caused due to erroneous installation.Incidentally, at this time, since the electrode terminal in the side ofthe electronic appliance comes into contact with the front face 36 c ofthe top cover 36 made of a synthetic resin, it is prevented from theoccurrence of direct contact with the metallic battery can 2.

On the other hand, what plural battery chargers are prepared for everyfunction even at the time of charging the secondary battery 1 requires auser to use a battery charger for each purpose and is complicated.Furthermore, this also requires a product supplier to manufacture andmanage plural kinds of battery chargers so that it is complicated.

Then, in the present battery charger 80, with respect to pluralsecondary batteries 1 having a different position of the positiveelectrode terminal part 37 and the negative electrode terminal part 38for every function, change of the installation direction makes itpossible to achieve common use. Concretely, in the secondary battery 1,since the positive electrode terminal part 37 and the negative electrodeterminal part 38 are arranged in a position of substantial pointsymmetry for every function, as illustrate in FIG. 31, when a secondarybattery 113 in which the positive electrode terminal part 37 and thenegative electrode terminal part 38 are arranged in a position ofsubstantial point symmetry is rotated through 180 degrees against asecondary battery 1A, the positive electrode terminal part 37 and thenegative electrode terminal part 38 of the both become the samepositions. Accordingly, in the case where the secondary battery 1A isinstalled in the battery charge 80, an upper face 1 a in the side of theshort side is positioned upwardly; and in the case where the secondarybattery 1B is installed in the battery charger 80, it is rotated through180 degrees such that a lower face 1 b is positioned downwardly. In thisway, in all of the secondary batteries 1A, 1B, charging can be carriedout by bringing the positive electrode terminal part 37 and the negativeelectrode terminal part 38 into contact with the electrode terminal 83as formed in the side of the battery charger 80.

Incidentally, it is possible to easily confirm whether or not each ofthe positive electrode terminal part 37 and the negative electrodeterminal part 38 comes into contact with the electrode terminal 83 ofthe battery charger 81 through the transparent part 84 regardless of theinstallation direction regarding the secondary batteries 1A, 1B. Also,the correctness of the installation direction regarding the secondarybatteries 1A, 1B can be confirmed by a display part for displaying thecharging state or the like.

Here, in the case where the secondary battery 1A is installed in such amanner that the lower face 1 b is faced upwardly and the secondarybattery 1B is installed in such a manner that the upper face 1 a isfaced upwardly, since each of the positive electrode terminal part 37and the negative electrode terminal part 38 does not come into contactwith the electrode terminal 83, charging is not achieved. At this time,since the electrode terminal 83 comes into contact with the front face36 c of the top cover 36 made of a synthetic resin, it is prevented fromthe occurrence of direct contact with the metallic battery can 2.Furthermore, even in the case where the secondary batteries 1A, 1B areinstalled in such a manner that the front face 1 a and the back face 1 dare reversed, since the electrode terminal 83 comes into contact withthe back face 1 d of the secondary battery 1, charging is not achieved.At this time, since the electrode terminal 83 is brought into contactwith the first winding part 17 of the external label 15 as stuck on thebottom face of the battery can 2, it is prevented from the occurrence ofdirect contact with the metallic battery can 2.

Furthermore, such a compatible battery charger may be configured asfollows. As illustrated in FIG. 32, a battery charger 90 is providedwith a battery charger main body 91 in a substantially rectangularshape, a holding arm 92 which is slidably supported by side faces 91 a,91 b of the battery charger main body 91 opposing to each other andwhich supports the secondary battery 1, and an electrode terminal 93 asprovided on a front face 91 c of the battery charger main body 91. Inthis battery charger 90, the secondary battery 1A or 1B in which thepositive electrode terminal part 37 and the negative electrode terminalpart 38 are arranged in a position of substantial point symmetry isinstalled from one direction or the other direction of the holding arm92 which holds the secondary battery 1.

The holding arm 92 is provided with one pair of arm parts 95, 95 whichare slidably supported by the both side faces 91 a, 91 b of the batterycharger main body 91 and a holding part 96 which is provided over onepair of the arm parts 95, 95 in tip parts of the arm parts 95, 95 andwhich holds the secondary battery 1A or 1B.

The arm parts 95, 95 are a longitudinal member and when slidablysupported by the both side faces 91 a, 91 b of the battery charger mainbody 91 at an interval substantially equal to the width of the secondarybattery 1, is drawn out into the side of the front face 91 c of thebattery charger main body 91. The holding part 96 which is formed in thetip parts of the arm parts 95, 95 is a member in a substantiallyT-shaped form which supports the battery can 2 of the secondary battery1 and has a supporting wall 97 which configures a front face of thebattery charger main body 91 and which supports the bottom face part ofthe battery can 2 and a placing face part 98 which projects fromsubstantially the center in the height direction of the supporting wall97 towards the side of the front face 91 c of the battery charger mainbody 91 over the arm parts 95, 95 and in which the both faces thereofare placing faces 98 a, 98 b on which a rear end part of the battery can2 is placed.

When the arm parts 95, 95 are slid in the side of the back face 91 d ofthe battery charger main body 91, the supporting wall 97 becomes a frontface of the battery charger main body 91. Furthermore, when the armparts 95, 95 are slid in the side of the front face 91 c of the batterycharger main body 91 and the secondary battery 1 is installed in thesupporting arm 92, the supporting wall 97 supports the bottom face part7 of the battery can 2.

In the placing face part 98, in the direction from the supporting wall97 to the side of the front face 91 c of the battery charger main body91, the placing faces 98 a, 98 b are each an inclination face asinclined towards the center in the thickness direction of the front face91 c. Further, in installing the secondary battery 1 in the holding arm92, the rear end part of the battery can 2 is placed, and the placingface part 98 is inclined in such a manner that the front face 36 c ofthe top cover 36 from which the positive electrode terminal part 37 andthe negative electrode terminal part 38 are faced is able to come intocontact with the electrode terminal 93 as formed on the front face 91 cof the battery charger main body 91. That is, when the rear end part ofthe battery can 2 is placed on the both placing faces 98 a, 98 b of theplacing face part 98, the positive electrode terminal part 37 and thenegative electrode terminal part 38 are brought into contact with theelectrode terminal 93 of the battery charger main body 91.

The holding arm 92 holds the secondary battery 1 by one pair of the armparts 95, 95, the placing face 98 a or placing face 98 b, and thesupporting wall 97. At this time, as illustrated in FIGS. 33A and 33B,the holding arm 92 holds the secondary battery 1A in which the positiveelectrode terminal part 37 and the negative electrode terminal part 38are arranged in a position of substantial point symmetry each on theplacing face 98 a and the secondary battery 1B on the placing face 98 b,respectively depending upon the function. At this time, each of thesecondary batteries 1A, 1B is installed in the holding arm 92 in such amanner that each lower face 1 b is an insertion face. Furthermore, thesecondary battery 1A which is held on the placing face 98 a and thesecondary battery 1B which is held on the placing face 98 b areinstalled while being rotated through 180 degrees each other. In thisway, in all of the secondary batteries 1A, 1B, since the positiveelectrode terminal part 37 and the negative electrode terminal part 38are turned to the same position, they come into contact with theelectrode terminal 93 as formed in the side of the front face 91 c ofthe battery charger main body 91, whereby charging can be achieved.

Incidentally, in the case where the secondary batteries 1A, 1B areinstalled from the side of the upper face 1 a while reversing theinsertion face, in the case where the secondary battery 1A is installedin the side of the placing face 98 b, or in the case where the secondarybattery 1B is installed in the side of the placing face 98 a, since thepositive electrode terminal part 37 and the negative electrode terminalpart 38 do not come into contact with the electrode terminal 93 asformed on the front face 91 c of the battery charge main body 91,charging is not achieved. At this time, since the electrode terminal 93comes into contact with the front 36 c of the top cover 36 made of asynthetic resin, it is prevented from the occurrence of direct contactwith the metallic battery can 2. Also, in the case where the secondarybatteries 1A, 1B are installed while reversing the upper faces 1 a andthe back faces 1 d, they are not charged because the electrode terminal93 comes in contact with the back faces 1 d of the secondary batteries1A and 1B. In this case, the electrode terminal 93 is prevented fromcoming in direct contact with the battery can 2 made of a metal becausethe electrode terminal 93 comes in contact with the first winding part17 of the external label 15 stuck on the bottom face of the battery can2.

Furthermore, as illustrated in FIG. 34, since at the time of non-use,the arm parts 95, 95 can be slid in the side of the back face 91 d ofthe battery charger main body 91, the battery charger 90 is excellent inportable properties and is able to prevent the breakage of the arm parts95, 95 or the like.

Furthermore, such a compatible battery charger may be configured asfollows. As illustrated in FIG. 35, a battery charger 100 is providedwith a battery charger main body 101 in a substantially rectangularshape, a battery installing part 102 as provided on an upper face 101 aof the battery charger main body 101, an electrode terminal 103 which isformed within the battery installing part 102 and which comes intocontact with the positive electrode terminal part 37 and the negativeelectrode terminal part 38 of the secondary battery 1, and one pair ofbattery holders 104A, 104B which are rotatably provided on the upperface 101 a of the battery charger main body 101 and which hold thesecondary batteries 1A, 1B. In this battery charger 100, by installingin the battery holder 104A or 104B by altering the direction of thesecondary battery 1 depending upon the arrangement of the positiveelectrode terminal part and the negative electrode terminal part 38,thereby enabling the electrode terminal 103 of the battery installingpart 102 to come into contact with the positive electrode terminal part37 and the negative electrode terminal part 38, not only compatibilityof plural kinds of secondary batteries 1A, 1B is ensured, but also inthe case where the direction is improper, insertion in the batteryholder 104A or 104B is inhibited. Thus, erroneous installation of thesecondary batteries 1A, 1B is prevented.

The battery charge main body 101 is formed in a substantiallyrectangular box-like shape, and the battery installing part 102 in whichthe secondary battery 1 is installed from the side of the front face 1 cis formed in substantially the center of the upper face 101 a.Furthermore, in the battery charger main body 101, one pair of thebattery holders 104A, 104B are provided rotatably towards the upperdirection on the upper face 101 a.

The battery installing part 102 is a concave in which the secondarybattery 1 is installed from the side of the front face and is opened ina substantially rectangular shape depending upon the shape of thesecondary battery 1. In the bottom face part of the battery installingpart 102, the electrode terminal 103 which comes into contact with thepositive electrode terminal part 37 and the negative electrode terminalpart 38 which are faced from the front face 1 c of the secondary battery1 is formed.

The battery holders 104A, 104B hold the secondary batteries 1A, 1B whichare installed in the battery installing part 102, and the battery holder104A holds the secondary battery 1A as illustrated in FIG. 36A, and thebattery holder 104B holds the secondary battery 1B as illustrated inFIG. 36B, respectively. The battery holders 104A, 104B have batteryaccommodating parts 105A, 105B for accommodating the secondary battery 1therein and one pair of arm parts 106A, 106B which are continuouslyprojected and formed from one pair of side faces of each of the batteryaccommodating parts 105A, 105B and which are rotatably supported by thebattery charger main body 101, respectively. Further, the battery holder104A is formed such that the battery accommodating part 105A is rotabletowards the upper direction from the side of the front face of the upperface 101 a of the battery charger main body 101 while using the base endparts of one pair of the arm parts 106A as a rotation fulcrum; and thebattery holder 104B is formed such that it is rotatable towards theupper direction from the side of the back face of the upper face 101 aof the battery charger main body 101 while using the base end parts ofone pair of the arm parts 106B as a rotation fulcrum.

The battery accommodating parts 105A, 105B are formed in a substantiallyrectangular box-like shape depending upon the shape of the secondarybattery 1, and one principal face thereof from which the secondarybattery 1 is inserted into and detached and a lower face thereof in theside of the battery installing part 102 are opened. Furthermore, thebattery accommodating parts 105A, 105B can be installed by inserting thesecondary battery 1 from the side of the lower face 1 b.

The battery holders 104A, 104B are installed in such a manner that whenthe battery accommodating part 105A and the battery accommodating part105B are rotated upwards the battery charger main body 101, the openingsides of the respective principal faces are faced opposite to eachother. That is, in the battery accommodating parts 105A, 105B, wheninstalled on the upper face 101 a of the battery charger main body 101,each of the back face walls thereof is faced upwardly as illustrated inFIG. 35; and when rotated upwardly, in the battery holder 104A, the backface wall of the battery accommodating part 105A is faced in the side ofthe back face of the battery charger main body 101 as illustrated inFIG. 36A, whereas in the battery holder 104B, the back face wall of thebattery accommodating part 105B is faced in the side of the front faceof the battery charger main body 101 as illustrated in FIG. 36B. In thisway, the secondary battery 1A which is installed in the battery holder104A and the secondary battery 1B which is installed in the batteryholder 104B are installed in an opposite direction to each other withrespect to the battery installing part 102 as provided on the upper face101 a of the battery charger main body 101.

One pair of the arm parts 106A, 106B are rotatably supported whilesandwiching the battery installing part 102 of the battery charger mainbody 101 therebetween; and when rotated in the side of the front face orin the side of back face of the battery charger main body 101, they holdthe battery holders 104, 104B substantially flush with the upper face101 a, whereas when rotated upwardly, they raise up the battery holders104A, 104B, thereby enabling the secondary battery 1 to be installedtherein.

In one pair of the arm parts 106A, 106B, the respective base end partsare supported while sandwiching both end parts in the longitudinaldirection of the battery installing part 102 as provided on the upperface 101 a of the battery charger main body 101. Furthermore, since thebattery holder 104A is formed so as to have a width narrower than thebattery holder 104B, the base end part of the arm part 106A is supportedin the battery charger main body 101 more inwardly than the base endpart of the arm part 106B. In this way, in the battery holder 104A andthe battery holder 105B, when either one of them is rotated upwardly,the rotation of the other is inhibited. Thus, only one of the secondarybattery 1A or the secondary battery 1B always comes into contact withthe electrode terminal 103.

In charging the secondary batteries 1A, 1B in which the positiveelectrode terminal part 37 and the negative electrode terminal part 38are arranged in a position of substantial point symmetry for everyfunction by using the foregoing battery charger 100, either one of thebattery holder 104A or 104B is rotated upwardly depending upon theposition of the terminal of the secondary battery 1. In the case wherethe battery holder 104A is rotated upwardly (see FIG. 36A), thesecondary battery 1A is inserted into the battery accommodating part105A in such a manner that the lower face 1 b is the insertion end face.In this way, in the secondary battery 1A, the side of the front face 1 cis installed in the battery installing part 102, and the positiveelectrode terminal part 37 and the negative electrode terminal part 38come into contact with the electrode terminal 103, thereby achievingcharging.

Incidentally, in the case where it is intended to insert the secondarybattery 1A from the side of the upper face 1 a, the insertion into thebattery accommodating part 105A is inhibited. Furthermore, in the casewhere the secondary battery 1B is inserted into the battery holder 104A,since the position of the positive electrode terminal part 37 and thenegative electrode terminal part 38 is formed opposite such that it isrotated through 180 degrees, the positive electrode terminal part 37 andthe negative electrode terminal part 38 do not come into contact withthe electrode terminal 103 of the battery installing part 102, wherebycharging is not achieved. At this time, since the electrode terminal 103comes into contact with the front face 36 c of the top cover 36 made ofa synthetic resin, it is prevented from the occurrence of direct contactwith the metallic battery can 2. Furthermore, in the case where thesecondary battery 1A is inserted inverted, since the electrode terminal103 comes into contact with the back side 1 d of the secondary battery1, charging is not achieved. At this time, since the electrode terminal103 comes into contact with the first winding part 17 of the externallabel 15 as stuck in the bottom face part 7 of the battery can 2, it isprevented from the occurrence of direct contact with the metallicbattery can 2.

Furthermore, in the case where the battery holder 104B is rotatedupwardly (see FIG. 36B), the secondary battery 1B is inserted into thebattery accommodating part 105B in such a manner that the lower face 1 bis the insertion end face. In this way, in the secondary battery 1B, theside of the front face 1 c is installed in the battery installing part102. Here, since the positive electrode terminal part 37 and thenegative electrode terminal part 38 are formed in a position ofsubstantial point symmetry against the secondary battery 1A, when thesecondary battery 1B is inserted into the battery accommodating part105B in a reverse direction to the secondary battery 1A as inserted intothe battery accommodating part 105A, the positive electrode terminalpart 37 and the negative electrode terminal part 38 turn to the samepositions as in the secondary battery 1A with respect to the electrodeterminal 103 of the battery installing part 102. Accordingly, in thesecondary battery 1B, the positive electrode terminal part 37 and thenegative electrode terminal part 38 come into contact with the electrodeterminal 103, thereby achieving charging.

Incidentally, in the case where it is intended to insert the secondarybattery 1B from the side of the upper face 1 a, the insertion into thebattery accommodating part 105B is inhibited. Furthermore, in the casewhere the secondary battery 1A is inserted into the battery holder 104B,since the position of the positive electrode terminal part 37 and thenegative electrode terminal part 38 is formed opposite such that it isrotated through 180 degrees, the positive electrode terminal part 37 andthe negative electrode terminal part 38 do not come into contact withthe electrode terminal 103 of the battery installing part 102, wherebycharging is not achieved. At this time, since the electrode terminal 103comes into contact with the front face 36 c of the top cover 36 made ofa synthetic resin, it is prevented from the occurrence of direct contactwith the metallic battery can 2. Furthermore, in the case where thesecondary battery 1B is inserted inverted, since the electrode terminal103 comes into contact with the back side 1 d of the secondary battery1, charging is not achieved. At this time, since the electrode terminal103 comes into contact with the first winding part 17 of the externallabel 15 as stuck in the bottom face part 7 of the battery can 2, it isprevented from the occurrence of direct contact with the metallicbattery can 2.

In the light of the above, in all of the secondary batteries 1A, 1B,since the positive electrode terminal part 37 and the negative electrodeterminal part 38 turn to the same positions, the positive electrodeterminal part 37 and the negative electrode terminal part 38 come intocontact with the electrode terminal 103 as formed in the batteryinstalling part 102, thereby achieving charging. Thus, it is possible tocommonly use the battery charger 100.

Furthermore, in the battery charger 90, since at the time of non-use,the battery holder 104 can be rotated in the side of the upper side 101a of the battery charger main body 101, the battery charger 90 isexcellent in portable properties and is able to prevent the breakage ofthe battery holder 104.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alternations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A secondary battery for an electronic appliance, comprising: a battery cell including a positive electrode, a negative electrode, and an electrolyte in a pack, a positive electrode terminal and a negative electrode terminal from the positive electrode and the negative electrode, respectively being each led out from a first side face of the battery cell; a battery cell holder including a face part and two opposing longitudinal faces, the battery cell holder accommodating the battery cell therein; and a cover including a terminal part configured to be connected to the positive and negative electrodes upon being connected to the positive electrode terminal and the negative electrode terminal and being faced outwardly, the cover adjoining the battery cell holder, wherein a cross section of an entirety of the secondary battery has a substantially trapezoidal flat plate shape including a long edge, a short edge that is shorter than the long edge, and opposing adjoining sides, which adjoin the long edge and the short edge, and wherein the terminal part is faced outwardly and is disposed closer to the short edge of the trapezoidal shape than to the long edge.
 2. The secondary battery according to claim 1, wherein the battery cell is inserted into the battery cell holder such that each side of the battery cell and each short side of the battery cell corresponds to a long side of the battery cell holder and a short side of the battery cell holder, respectively.
 3. The secondary battery according to claim 1, wherein a clearance exists between the battery cell and an inner periphery of the battery cell holder.
 4. The secondary battery according to claim 1, wherein a second side face of the battery cell opposes the first side face thereof and is adhered to a bottom face of the battery cell holder via an elastic member.
 5. The secondary battery according to claim 4, wherein the elastic member includes an insulating film which is arranged between a cut face of the pack and an inner wall of the battery cell holder.
 6. The secondary battery according to claim 1, wherein a principal face of the battery cell is adhered to a principal face of the battery cell holder by an adhesive disposed on the principal face of the battery cell holder.
 7. The secondary battery according to claim 1, wherein the battery cell is accommodated in the battery cell holder after folding an overlap width part of the pack along an outside face of the pack.
 8. The secondary battery according to claim 1, wherein the terminal part includes a positive terminal part and a negative terminal part. 